When i am towing my 4000 lb trailer, using a weight distribution hitch, set up properly by my rv specialist, with either unloaded or with a loaded weight not exceeding even 6000 pounds, the armada sinks in the back end in a way that the rear tires come extremely close to the wheel well rims. my rv specialist is very concerned that if i am driving and hit a bump or hole, the tire could strike the wheel well rim and cause a blow out or major accident. they are concerned the spring ratio is not designed properly for the armada (which has a tow package and is supposedly capable of towing 8500 pounds). i have brought this issue to nissan north america's attention and they will not even take a look at the problem, instead telling me that if an accident occurs, it is covered under my warranty!